The present invention relates to a means for establishing a firm and accurate platform upon which may be secured a sighting instrument, generally termed a collimater, in order to thereby enhance the accuracy of said collimater in its primary purpose of establishing a true line of sight from the telescope of the shotgun to the center of the prospective target.
Various patents in the prior art relate to collimating devices and to platform means associated therewith. An example of the state of the art in this area appears in U.S. Pat. No. 3,744,133 (1973) to Fukushima et al.
The platform securement means illustrated in said patent has, as in the case of other prior art means, been found to be less than satisfactory in its intended purpose of establishing a firm and accurate base upon which the collimater may be secured for alignment with the telescopic sight. More particularly, a special need for an improved sighting platform has been found to exist in the shotgun area.
The basic shortcoming in prior art designs has related to an absence of concentricity of the sighting platform with relationship to the bore of the gun. That is, in order to assure accuracy of the collimater, it is essential that the axis of the elongated member which will comprise the platform for the collimater be absolutely co-linear with the axis of the bore of the gun.
In light of the multitude of different diameters and contours of barrels of guns and, particularly, barrels of shotguns, it is essential that the exact center of each bore be located in order to appropriately establish the true line of sight from the telescope through the collimater to the center of the target. The present instrument is intended to do exactly this in that it serves to centralize the position of the platform of the collimater within any diameter of bore configuration throughout all generally known types of shotgun barrels.
Efforts in the prior art in attaining the above have been further encumbered by the fact that shotguns possess extremely high mirror-like finishes on the inside of their barrels. Accordingly, it is necessary, in order to attain the most beneficial function, to attain a device that will not twist, scratch or mar the mirror-like surface but which will, nonetheless, not slip, slide or otherwise move within the desired perfectly concentric placement within the bore. This problem has, in the prior art, proven to be a formidable one. Accordingly, the present invention is intended as a solution to said problem.